One former student of mine learnt to fly after surviving throat cancer. They had removed all his saliva glands so a water bottle was a constant companion in the C150.
This constant water intake meant he had pretty good bladder control but one day yes, he was caught short.
First problem was that his water bottle was still part full. Not knowing when he could get more water, he chose to drink it then and there. In so doing he missed a valuable lesson.
He wriggled about to get his equipment pointed at the little water bottle which led to problem 2- bladder bigger than bottle and he was going to overflow.
Logically, he decided to empty the bottle out the window. While pinching Percy tightly, juggling flight controls and bottle full to brimming, he opened the pilots window of the C150 and tipped out.
....from the front of the window opening.
Problem 3 was the circulation of the airflow which blew all the effluvium back in at the rear of the window, at which he let go of the bottle and used both hands to shut the window.
Problem 4 was that he had just let go of Percy....